Microbes Provide Solutions to Energy Issues

After three years of research, Gemma Reguera has developed a process that can be harnessed to produce clean, cheap electricity and fuel from plant biomass.

September 18, 2009

After three years of research, Gemma Reguera, MAES microbiology and molecular genetics and crop and soil sciences researcher, has developed a process that can be harnessed to produce clean, cheap electricity and fuel from plant biomass.

Using a specific selection of metal-reducing microorganisms in the Geobacter species -- bacteria that are natural inhabitants of environments abundant in metals -- Reguera was able to design a microbial fuel cell that acts as a natural battery to convert plant biomass into electrical power and produces a high-yield, low-cost cellulosic ethanol product.

"Finding the exact combination was difficult because there are billions of microbes living in the soil and water," Reguera said. "By observing the natural processes of these organisms over time, we were able to reproduce these processes and develop a technology by matching up the right microbes.

"All the work of this process is done by bacteria inside a microbial fuel cell," Reguera said. "Some of the bacteria decompose plant material; others move electrons to survive. The electron-moving microorganisms such as those in Geobacter naturally replace metal oxides with electrodes to get energy. This process is similar to how we breathe oxygen and exhale carbon dioxide."

She said that producing ethanol is viewed as the main purpose, but having the fuel cell create electrical power as a byproduct has added benefits. In the future, farms could be powered by their own plant byproducts and fuel their tractors from the same microbial fuel cell.

Microbial fuel cells are attracting interest because they are inexpensive to manufacture and produce no harmful byproducts.

Reguera also is a member of the Great Lakes Bioenergy Research Center (GLBRC), a partnership between Michigan State and the University of Wisconsin-Madison funded by the U.S. Department of Energy (DOE) to conduct basic research aimed at solving some of the most complex problems in converting natural materials to energy.

As part of her work with the GLBRC, Reguera has modified a type of Geobacter to live in the same conditions as Cyanobacteria. Cyanobacteria are bacteria that produce energy from sunlight. The combination of these two types of bacteria means that the fuel cells can produce electricity directly from sunlight.

Reguera's next step is to make the fuel cells more efficient and successful at a larger scale. A team of Australian researchers is currently experimenting with microbial fuel cells to treat wastewater effluent from a brewery while producing power. Microbial fuel cells are also being tested in ethanol biorefineries to remove toxic products from biomass pretreatments while generating about 25 percent of a biorefinery?s electrical power needs.

"I tell my students 'you have to be very brave to be in my lab' because they have to know how to do the entire process from the primary research to application," Reguera said. "But they get really motivated when they see how small technologies can make huge impacts."

In addition to the MAES and the GLBRC, Reguera's work is funded by the Rackham Fund Foundation.